median() function

Warning! This page documents an earlier version of Flux, which is no longer actively developed. Flux v0.24 is the most recent stable version of Flux.

The median() function is a special application of the percentile() function
that returns the median _value of an input table or all non-null records in the input table
with values that fall within the 50th percentile depending on the method used.

Function type: Selector or AggregateOutput data type: Object

median(method:"estimate_tdigest",compression:0.0)

When using the estimate_tdigest or exact_mean methods, it outputs non-null
records with values that fall within the 50th percentile.

When using the exact_selector method, it outputs the non-null record with the
value that represents the 50th percentile.

The median() function can only be used with float value types.
It is a special application of the percentile() function which
uses an approximation implementation that requires floats.
You can convert your value column to a float column using the toFloat() function.

Parameters

method

Defines the method of computation. Defaults to "estimate_tdigest".

Data type: String

The available options are:

estimate_tdigest

An aggregate method that uses a t-digest data structure
to compute an accurate percentile estimate on large data sources.

exact_mean

An aggregate method that takes the average of the two points closest to the percentile value.

exact_selector

A selector method that returns the data point for which at least percentile points are less than.

compression

Indicates how many centroids to use when compressing the dataset.
A larger number produces a more accurate result at the cost of increased memory requirements.
Defaults to 1000.